Report from SCCT: Dual-source cardiac CTA protocol lowers radiation exposure

Automated minimal dosing combined with other strategies can cut patient radiation exposure in half during dual-source coronary CT angiography, according to a study by German researchers presented at the 2007 Society of Cardiovascular Computed Tomography meeting. Several studies have demonstrated the value of automated tube current modulation, or ECG-pulsing, to reduce radiation doses in multislice CTA studies. The same concept has been used successfully for dose reductions of about 36% in 64-slice CTA. Applying a new algorithm called MinDose, which minimizes tube current during the systolic phase, could lead to further dose savings and could also be done with dual-source CT systems, said principal investigator Dr. Jorg Hausleiter, a staff physician at the Clinic for Cardiovascular Disease/German Heart Center in Munich.

Hausleiter and colleagues assessed 30 consecutive patients who were split in four groups to undergo the following CTA scanning protocols:

• group A: 120 kV tube voltage and conservative ECG-pulsing
• group B: 100 kV and conservative ECG-pulsing
• group C: 100 kV and adapted, or "narrow," ECG-pulsing
• group D: 100 kV with adapted ECG-pulsing and MinDose

The investigators achieved estimated radiation doses of about 13, 7, 6, and <5 mSv for groups A, B, C, and D, respectively. Compared with the 120 kV protocol, all the other protocols resulted in significantly reduced dose estimates (p<0.01). These dose-saving protocols did not diminish image quality, with more than 98% of the studies reaching diagnostic quality, Hausleiter said.

"Dose saving strategies for coronary DSCT are efficient and should be used whenever possible to reduce patients' radiation burden. Our recently developed MinDose algorithm represents a new effective tool for further radiation dose reduction," he said.For more information from the Diagnostic Imaging archives:

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